Assign mass to a part (Edit: Using Catia)

Hi,
I am using the measuring tool to measure the moment of inertia of one of my parts, but I want to change the mass of the part to a specific value, so I can get the correct moment of inertia to the actual part. (the mass is uniformly distributed in the part). Is there a way I can do this without having to find a material in the material browser that somewhat matches my desired mass? 

Edu ​​​​​​​3DEXPERIENCE ​​​​​​​CATIA ​​​​​​​